ParseDeclCXX.cpp revision 4cc18a4d5222e04bd568b1e3e4d86127dbbcdf3f 
1//===--- ParseDeclCXX.cpp - C++ Declaration Parsing -----------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file implements the C++ Declaration portions of the Parser interfaces.
11//
12//===----------------------------------------------------------------------===//
13
14#include "clang/Parse/Parser.h"
15#include "clang/Basic/Diagnostic.h"
16#include "clang/Parse/DeclSpec.h"
17#include "clang/Parse/Scope.h"
18using namespace clang;
19
20/// ParseNamespace - We know that the current token is a namespace keyword. This
21/// may either be a top level namespace or a block-level namespace alias.
22///
23///       namespace-definition: [C++ 7.3: basic.namespace]
24///         named-namespace-definition
25///         unnamed-namespace-definition
26///
27///       unnamed-namespace-definition:
28///         'namespace' attributes[opt] '{' namespace-body '}'
29///
30///       named-namespace-definition:
31///         original-namespace-definition
32///         extension-namespace-definition
33///
34///       original-namespace-definition:
35///         'namespace' identifier attributes[opt] '{' namespace-body '}'
36///
37///       extension-namespace-definition:
38///         'namespace' original-namespace-name '{' namespace-body '}'
39///
40///       namespace-alias-definition:  [C++ 7.3.2: namespace.alias]
41///         'namespace' identifier '=' qualified-namespace-specifier ';'
42///
43Parser::DeclTy *Parser::ParseNamespace(unsigned Context) {
44  assert(Tok.is(tok::kw_namespace) && "Not a namespace!");
45  SourceLocation NamespaceLoc = ConsumeToken();  // eat the 'namespace'.
46
47  SourceLocation IdentLoc;
48  IdentifierInfo *Ident = 0;
49
50  if (Tok.is(tok::identifier)) {
51    Ident = Tok.getIdentifierInfo();
52    IdentLoc = ConsumeToken();  // eat the identifier.
53  }
54
55  // Read label attributes, if present.
56  DeclTy *AttrList = 0;
57  if (Tok.is(tok::kw___attribute))
58    // FIXME: save these somewhere.
59    AttrList = ParseAttributes();
60
61  if (Tok.is(tok::equal)) {
62    // FIXME: Verify no attributes were present.
63    // FIXME: parse this.
64  } else if (Tok.is(tok::l_brace)) {
65
66    SourceLocation LBrace = ConsumeBrace();
67
68    // Enter a scope for the namespace.
69    EnterScope(Scope::DeclScope);
70
71    DeclTy *NamespcDecl =
72      Actions.ActOnStartNamespaceDef(CurScope, IdentLoc, Ident, LBrace);
73
74    while (Tok.isNot(tok::r_brace) && Tok.isNot(tok::eof))
75      ParseExternalDeclaration();
76
77    // Leave the namespace scope.
78    ExitScope();
79
80    SourceLocation RBrace = MatchRHSPunctuation(tok::r_brace, LBrace);
81    Actions.ActOnFinishNamespaceDef(NamespcDecl, RBrace);
82
83    return NamespcDecl;
84
85  } else {
86    unsigned D = Ident ? diag::err_expected_lbrace :
87                         diag::err_expected_ident_lbrace;
88    Diag(Tok.getLocation(), D);
89  }
90
91  return 0;
92}
93
94/// ParseLinkage - We know that the current token is a string_literal
95/// and just before that, that extern was seen.
96///
97///       linkage-specification: [C++ 7.5p2: dcl.link]
98///         'extern' string-literal '{' declaration-seq[opt] '}'
99///         'extern' string-literal declaration
100///
101Parser::DeclTy *Parser::ParseLinkage(unsigned Context) {
102  assert(Tok.is(tok::string_literal) && "Not a stringliteral!");
103  llvm::SmallVector<char, 8> LangBuffer;
104  // LangBuffer is guaranteed to be big enough.
105  LangBuffer.resize(Tok.getLength());
106  const char *LangBufPtr = &LangBuffer[0];
107  unsigned StrSize = PP.getSpelling(Tok, LangBufPtr);
108
109  SourceLocation Loc = ConsumeStringToken();
110  DeclTy *D = 0;
111  SourceLocation LBrace, RBrace;
112
113  if (Tok.isNot(tok::l_brace)) {
114    D = ParseDeclaration(Context);
115  } else {
116    LBrace = ConsumeBrace();
117    while (Tok.isNot(tok::r_brace) && Tok.isNot(tok::eof)) {
118      // FIXME capture the decls.
119      D = ParseExternalDeclaration();
120    }
121
122    RBrace = MatchRHSPunctuation(tok::r_brace, LBrace);
123  }
124
125  if (!D)
126    return 0;
127
128  return Actions.ActOnLinkageSpec(Loc, LBrace, RBrace, LangBufPtr, StrSize, D);
129}
130
131/// ParseClassSpecifier - Parse a C++ class-specifier [C++ class] or
132/// elaborated-type-specifier [C++ dcl.type.elab]; we can't tell which
133/// until we reach the start of a definition or see a token that
134/// cannot start a definition.
135///
136///       class-specifier: [C++ class]
137///         class-head '{' member-specification[opt] '}'
138///         class-head '{' member-specification[opt] '}' attributes[opt]
139///       class-head:
140///         class-key identifier[opt] base-clause[opt]
141///         class-key nested-name-specifier identifier base-clause[opt]
142///         class-key nested-name-specifier[opt] simple-template-id
143///                          base-clause[opt]
144/// [GNU]   class-key attributes[opt] identifier[opt] base-clause[opt]
145/// [GNU]   class-key attributes[opt] nested-name-specifier
146///                          identifier base-clause[opt]
147/// [GNU]   class-key attributes[opt] nested-name-specifier[opt]
148///                          simple-template-id base-clause[opt]
149///       class-key:
150///         'class'
151///         'struct'
152///         'union'
153///
154///       elaborated-type-specifier: [C++ dcl.type.elab]
155///         class-key ::[opt] nested-name-specifier[opt] identifier
156///         class-key ::[opt] nested-name-specifier[opt] 'template'[opt]
157///                          simple-template-id
158///
159///  Note that the C++ class-specifier and elaborated-type-specifier,
160///  together, subsume the C99 struct-or-union-specifier:
161///
162///       struct-or-union-specifier: [C99 6.7.2.1]
163///         struct-or-union identifier[opt] '{' struct-contents '}'
164///         struct-or-union identifier
165/// [GNU]   struct-or-union attributes[opt] identifier[opt] '{' struct-contents
166///                                                         '}' attributes[opt]
167/// [GNU]   struct-or-union attributes[opt] identifier
168///       struct-or-union:
169///         'struct'
170///         'union'
171void Parser::ParseClassSpecifier(DeclSpec &DS) {
172  assert((Tok.is(tok::kw_class) ||
173          Tok.is(tok::kw_struct) ||
174          Tok.is(tok::kw_union)) &&
175         "Not a class specifier");
176  DeclSpec::TST TagType =
177    Tok.is(tok::kw_class) ? DeclSpec::TST_class :
178    Tok.is(tok::kw_struct) ? DeclSpec::TST_struct :
179    DeclSpec::TST_union;
180
181  SourceLocation StartLoc = ConsumeToken();
182
183  AttributeList *Attr = 0;
184  // If attributes exist after tag, parse them.
185  if (Tok.is(tok::kw___attribute))
186    Attr = ParseAttributes();
187
188  // FIXME: Parse the (optional) nested-name-specifier.
189
190  // Parse the (optional) class name.
191  // FIXME: Alternatively, parse a simple-template-id.
192  IdentifierInfo *Name = 0;
193  SourceLocation NameLoc;
194  if (Tok.is(tok::identifier)) {
195    Name = Tok.getIdentifierInfo();
196    NameLoc = ConsumeToken();
197  }
198
199  // There are three options here.  If we have 'struct foo;', then
200  // this is a forward declaration.  If we have 'struct foo {...' or
201  // 'struct fo :...' then this is a definition. Otherwise we have
202  // something like 'struct foo xyz', a reference.
203  Action::TagKind TK;
204  if (Tok.is(tok::l_brace) || (getLang().CPlusPlus && Tok.is(tok::colon)))
205    TK = Action::TK_Definition;
206  else if (Tok.is(tok::semi))
207    TK = Action::TK_Declaration;
208  else
209    TK = Action::TK_Reference;
210
211  if (!Name && TK != Action::TK_Definition) {
212    // We have a declaration or reference to an anonymous class.
213    Diag(StartLoc, diag::err_anon_type_definition,
214         DeclSpec::getSpecifierName(TagType));
215
216    // Skip the rest of this declarator, up until the comma or semicolon.
217    SkipUntil(tok::comma, true);
218    return;
219  }
220
221  // Parse the tag portion of this.
222  DeclTy *TagDecl = Actions.ActOnTag(CurScope, TagType, TK, StartLoc, Name,
223                                     NameLoc, Attr);
224
225  // Parse the optional base clause (C++ only).
226  if (getLang().CPlusPlus && Tok.is(tok::colon)) {
227    ParseBaseClause(TagDecl);
228  }
229
230  // If there is a body, parse it and inform the actions module.
231  if (Tok.is(tok::l_brace))
232    // FIXME: Temporarily disable parsing for C++ classes until the Sema support
233    // is in place.
234    //if (getLang().CPlusPlus)
235    //  ParseCXXMemberSpecification(StartLoc, TagType, TagDecl);
236    //else
237      ParseStructUnionBody(StartLoc, TagType, TagDecl);
238  else if (TK == Action::TK_Definition) {
239    // FIXME: Complain that we have a base-specifier list but no
240    // definition.
241    Diag(Tok.getLocation(), diag::err_expected_lbrace);
242  }
243
244  const char *PrevSpec = 0;
245  if (DS.SetTypeSpecType(TagType, StartLoc, PrevSpec, TagDecl))
246    Diag(StartLoc, diag::err_invalid_decl_spec_combination, PrevSpec);
247}
248
249/// ParseBaseClause - Parse the base-clause of a C++ class [C++ class.derived].
250///
251///       base-clause : [C++ class.derived]
252///         ':' base-specifier-list
253///       base-specifier-list:
254///         base-specifier '...'[opt]
255///         base-specifier-list ',' base-specifier '...'[opt]
256void Parser::ParseBaseClause(DeclTy *ClassDecl)
257{
258  assert(Tok.is(tok::colon) && "Not a base clause");
259  ConsumeToken();
260
261  while (true) {
262    // Parse a base-specifier.
263    if (ParseBaseSpecifier(ClassDecl)) {
264      // Skip the rest of this base specifier, up until the comma or
265      // opening brace.
266      SkipUntil(tok::comma, tok::l_brace);
267    }
268
269    // If the next token is a comma, consume it and keep reading
270    // base-specifiers.
271    if (Tok.isNot(tok::comma)) break;
272
273    // Consume the comma.
274    ConsumeToken();
275  }
276}
277
278/// ParseBaseSpecifier - Parse a C++ base-specifier. A base-specifier is
279/// one entry in the base class list of a class specifier, for example:
280///    class foo : public bar, virtual private baz {
281/// 'public bar' and 'virtual private baz' are each base-specifiers.
282///
283///       base-specifier: [C++ class.derived]
284///         ::[opt] nested-name-specifier[opt] class-name
285///         'virtual' access-specifier[opt] ::[opt] nested-name-specifier[opt]
286///                        class-name
287///         access-specifier 'virtual'[opt] ::[opt] nested-name-specifier[opt]
288///                        class-name
289bool Parser::ParseBaseSpecifier(DeclTy *ClassDecl)
290{
291  bool IsVirtual = false;
292  SourceLocation StartLoc = Tok.getLocation();
293
294  // Parse the 'virtual' keyword.
295  if (Tok.is(tok::kw_virtual))  {
296    ConsumeToken();
297    IsVirtual = true;
298  }
299
300  // Parse an (optional) access specifier.
301  AccessSpecifier Access = getAccessSpecifierIfPresent();
302  if (Access)
303    ConsumeToken();
304
305  // Parse the 'virtual' keyword (again!), in case it came after the
306  // access specifier.
307  if (Tok.is(tok::kw_virtual))  {
308    SourceLocation VirtualLoc = ConsumeToken();
309    if (IsVirtual) {
310      // Complain about duplicate 'virtual'
311      Diag(VirtualLoc, diag::err_dup_virtual);
312    }
313
314    IsVirtual = true;
315  }
316
317  // FIXME: Parse optional '::' and optional nested-name-specifier.
318
319  // Parse the class-name.
320  // FIXME: Alternatively, parse a simple-template-id.
321  if (Tok.isNot(tok::identifier)) {
322    Diag(Tok.getLocation(), diag::err_expected_class_name);
323    return true;
324  }
325
326  // We have an identifier; check whether it is actually a type.
327  DeclTy *BaseType = Actions.isTypeName(*Tok.getIdentifierInfo(), CurScope);
328  if (!BaseType) {
329    Diag(Tok.getLocation(), diag::err_expected_class_name);
330    return true;
331  }
332
333  // The location of the base class itself.
334  SourceLocation BaseLoc = Tok.getLocation();
335
336  // Find the complete source range for the base-specifier.
337  SourceRange Range(StartLoc, BaseLoc);
338
339  // Consume the identifier token (finally!).
340  ConsumeToken();
341
342  // Notify semantic analysis that we have parsed a complete
343  // base-specifier.
344  Actions.ActOnBaseSpecifier(ClassDecl, Range, IsVirtual, Access, BaseType,
345                             BaseLoc);
346  return false;
347}
348
349/// getAccessSpecifierIfPresent - Determine whether the next token is
350/// a C++ access-specifier.
351///
352///       access-specifier: [C++ class.derived]
353///         'private'
354///         'protected'
355///         'public'
356AccessSpecifier Parser::getAccessSpecifierIfPresent() const
357{
358  switch (Tok.getKind()) {
359  default: return AS_none;
360  case tok::kw_private: return AS_private;
361  case tok::kw_protected: return AS_protected;
362  case tok::kw_public: return AS_public;
363  }
364}
365
366/// ParseCXXClassMemberDeclaration - Parse a C++ class member declaration.
367///
368///       member-declaration:
369///         decl-specifier-seq[opt] member-declarator-list[opt] ';'
370///         function-definition ';'[opt]
371///         ::[opt] nested-name-specifier template[opt] unqualified-id ';'[TODO]
372///         using-declaration                                            [TODO]
373/// [C++0x] static_assert-declaration                                    [TODO]
374///         template-declaration                                         [TODO]
375///
376///       member-declarator-list:
377///         member-declarator
378///         member-declarator-list ',' member-declarator
379///
380///       member-declarator:
381///         declarator pure-specifier[opt]
382///         declarator constant-initializer[opt]
383///         identifier[opt] ':' constant-expression
384///
385///       pure-specifier:   [TODO]
386///         '= 0'
387///
388///       constant-initializer:
389///         '=' constant-expression
390///
391Parser::DeclTy *Parser::ParseCXXClassMemberDeclaration(AccessSpecifier AS) {
392  SourceLocation DSStart = Tok.getLocation();
393  // decl-specifier-seq:
394  // Parse the common declaration-specifiers piece.
395  DeclSpec DS;
396  ParseDeclarationSpecifiers(DS);
397
398  if (Tok.is(tok::semi)) {
399    ConsumeToken();
400    // C++ 9.2p7: The member-declarator-list can be omitted only after a
401    // class-specifier or an enum-specifier or in a friend declaration.
402    // FIXME: Friend declarations.
403    switch (DS.getTypeSpecType()) {
404      case DeclSpec::TST_struct:
405      case DeclSpec::TST_union:
406      case DeclSpec::TST_class:
407      case DeclSpec::TST_enum:
408        return Actions.ParsedFreeStandingDeclSpec(CurScope, DS);
409      default:
410        Diag(DSStart, diag::err_no_declarators);
411        return 0;
412    }
413  }
414
415  // Parse the first declarator.
416  Declarator DeclaratorInfo(DS, Declarator::MemberContext);
417  ParseDeclarator(DeclaratorInfo);
418  // Error parsing the declarator?
419  if (DeclaratorInfo.getIdentifier() == 0) {
420    // If so, skip until the semi-colon or a }.
421    SkipUntil(tok::r_brace, true);
422    if (Tok.is(tok::semi))
423      ConsumeToken();
424    return 0;
425  }
426
427  // function-definition:
428  if (Tok.is(tok::l_brace)) {
429    if (!DeclaratorInfo.isFunctionDeclarator()) {
430      Diag(Tok, diag::err_func_def_no_params);
431      ConsumeBrace();
432      SkipUntil(tok::r_brace, true);
433      return 0;
434    }
435
436    if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
437      Diag(Tok, diag::err_function_declared_typedef);
438      // This recovery skips the entire function body. It would be nice
439      // to simply call ParseCXXInlineMethodDef() below, however Sema
440      // assumes the declarator represents a function, not a typedef.
441      ConsumeBrace();
442      SkipUntil(tok::r_brace, true);
443      return 0;
444    }
445
446    return ParseCXXInlineMethodDef(AS, DeclaratorInfo);
447  }
448
449  // member-declarator-list:
450  //   member-declarator
451  //   member-declarator-list ',' member-declarator
452
453  DeclTy *LastDeclInGroup = 0;
454  ExprTy *BitfieldSize = 0;
455  ExprTy *Init = 0;
456
457  while (1) {
458
459    // member-declarator:
460    //   declarator pure-specifier[opt]
461    //   declarator constant-initializer[opt]
462    //   identifier[opt] ':' constant-expression
463
464    if (Tok.is(tok::colon)) {
465      ConsumeToken();
466      ExprResult Res = ParseConstantExpression();
467      if (Res.isInvalid)
468        SkipUntil(tok::comma, true, true);
469      else
470        BitfieldSize = Res.Val;
471    }
472
473    // pure-specifier:
474    //   '= 0'
475    //
476    // constant-initializer:
477    //   '=' constant-expression
478
479    if (Tok.is(tok::equal)) {
480      ConsumeToken();
481      ExprResult Res = ParseInitializer();
482      if (Res.isInvalid)
483        SkipUntil(tok::comma, true, true);
484      else
485        Init = Res.Val;
486    }
487
488    // If attributes exist after the declarator, parse them.
489    if (Tok.is(tok::kw___attribute))
490      DeclaratorInfo.AddAttributes(ParseAttributes());
491
492    LastDeclInGroup = Actions.ActOnCXXMemberDeclarator(CurScope, AS,
493                                                       DeclaratorInfo,
494                                                       BitfieldSize, Init,
495                                                       LastDeclInGroup);
496
497    // If we don't have a comma, it is either the end of the list (a ';')
498    // or an error, bail out.
499    if (Tok.isNot(tok::comma))
500      break;
501
502    // Consume the comma.
503    ConsumeToken();
504
505    // Parse the next declarator.
506    DeclaratorInfo.clear();
507    BitfieldSize = Init = 0;
508
509    // Attributes are only allowed on the second declarator.
510    if (Tok.is(tok::kw___attribute))
511      DeclaratorInfo.AddAttributes(ParseAttributes());
512
513    ParseDeclarator(DeclaratorInfo);
514  }
515
516  if (Tok.is(tok::semi)) {
517    ConsumeToken();
518    // Reverse the chain list.
519    return Actions.FinalizeDeclaratorGroup(CurScope, LastDeclInGroup);
520  }
521
522  Diag(Tok, diag::err_expected_semi_decl_list);
523  // Skip to end of block or statement
524  SkipUntil(tok::r_brace, true, true);
525  if (Tok.is(tok::semi))
526    ConsumeToken();
527  return 0;
528}
529
530/// ParseCXXMemberSpecification - Parse the class definition.
531///
532///       member-specification:
533///         member-declaration member-specification[opt]
534///         access-specifier ':' member-specification[opt]
535///
536void Parser::ParseCXXMemberSpecification(SourceLocation RecordLoc,
537                                         unsigned TagType, DeclTy *TagDecl) {
538  assert(TagType == DeclSpec::TST_struct ||
539         TagType == DeclSpec::TST_union  ||
540         TagType == DeclSpec::TST_class && "Invalid TagType!");
541
542  SourceLocation LBraceLoc = ConsumeBrace();
543
544  if (!CurScope->isCXXClassScope() && // Not about to define a nested class.
545      CurScope->isInCXXInlineMethodScope()) {
546    // We will define a local class of an inline method.
547    // Push a new LexedMethodsForTopClass for its inline methods.
548    PushTopClassStack();
549  }
550
551  // Enter a scope for the class.
552  EnterScope(Scope::CXXClassScope|Scope::DeclScope);
553
554  Actions.ActOnStartCXXClassDef(CurScope, TagDecl, LBraceLoc);
555
556  // C++ 11p3: Members of a class defined with the keyword class are private
557  // by default. Members of a class defined with the keywords struct or union
558  // are public by default.
559  AccessSpecifier CurAS;
560  if (TagType == DeclSpec::TST_class)
561    CurAS = AS_private;
562  else
563    CurAS = AS_public;
564
565  // While we still have something to read, read the member-declarations.
566  while (Tok.isNot(tok::r_brace) && Tok.isNot(tok::eof)) {
567    // Each iteration of this loop reads one member-declaration.
568
569    // Check for extraneous top-level semicolon.
570    if (Tok.is(tok::semi)) {
571      Diag(Tok, diag::ext_extra_struct_semi);
572      ConsumeToken();
573      continue;
574    }
575
576    AccessSpecifier AS = getAccessSpecifierIfPresent();
577    if (AS != AS_none) {
578      // Current token is a C++ access specifier.
579      CurAS = AS;
580      ConsumeToken();
581      ExpectAndConsume(tok::colon, diag::err_expected_colon);
582      continue;
583    }
584
585    // Parse all the comma separated declarators.
586    ParseCXXClassMemberDeclaration(CurAS);
587  }
588
589  SourceLocation RBraceLoc = MatchRHSPunctuation(tok::r_brace, LBraceLoc);
590
591  AttributeList *AttrList = 0;
592  // If attributes exist after class contents, parse them.
593  if (Tok.is(tok::kw___attribute))
594    AttrList = ParseAttributes(); // FIXME: where should I put them?
595
596  Actions.ActOnFinishCXXMemberSpecification(CurScope, RecordLoc, TagDecl,
597                                            LBraceLoc, RBraceLoc);
598
599  // C++ 9.2p2: Within the class member-specification, the class is regarded as
600  // complete within function bodies, default arguments,
601  // exception-specifications, and constructor ctor-initializers (including
602  // such things in nested classes).
603  //
604  // FIXME: Only function bodies are parsed correctly, fix the rest.
605  if (!CurScope->getParent()->isCXXClassScope()) {
606    // We are not inside a nested class. This class and its nested classes
607    // are complete and we can parse the lexed inline method definitions.
608    ParseLexedMethodDefs();
609
610    // For a local class of inline method, pop the LexedMethodsForTopClass that
611    // was previously pushed.
612
613    assert(CurScope->isInCXXInlineMethodScope() ||
614           TopClassStacks.size() == 1    &&
615           "MethodLexers not getting popped properly!");
616    if (CurScope->isInCXXInlineMethodScope())
617      PopTopClassStack();
618  }
619
620  // Leave the class scope.
621  ExitScope();
622
623  Actions.ActOnFinishCXXClassDef(TagDecl, RBraceLoc);
624}
625